This is a continuation-in-part of U.S. application Ser. No. 057,006 filed on June 1, 1987, in the name of the same applicant, now abandoned.
The present invention relates to a rotating internal combustion engine provided with means for varying the compression ratio.
As is known, there are presently available the so-called Wankel type rotary engines which, however, have great drawbacks with respect to the gas tightness and do not afford the possibility of affecting, by modifying the variable volume chamber shape, the combustion conditions of the air/fuel mixture, depending on its turbulence and the formation of a proper flame front.
Moreover, these Wankel engines do not achieve very high compression ratio and they do not fully exploit the gas expansion force, because of the poor radial extension of the surface affected by the gas active pressure.
There are also known further rotary engines such as that disclosed in the U.S. Pat. No. 3,685,928 granted on Aug. 22, 1972 to Munzinger. More specifically this patent discloses a rotary piston engine, including a plurality of cylinder forming annular elements and a plurality of annular segment piston pairs, the segment piston of each pair moving inside one of said cylinders and having disc shaped articulated elements bearing against each other and defining together with their circumferenatial surfaces the inner wall of the corresponding cylinder, the hubs of one of the segment pistons of each pair having shaft portions axially extending therefrom and forming outer hollow shaft means and the hubs of the other pistons of each pair having shaft portions extending axially therefrom which form inner shaft means, the shaft portions of the inner shaft means being supported within the shaft portions of the outer shaft means, separating elements between each pair of piston segments forming the end walls of the cylinder, a common shaft, means operatively coupling the outer shaft means and inner shaft means to the common shaft, the hubs of the inner shaft means being provided with annular recesses therethrough at the same spacing from the axis of the shaft means as the distance separating the shaft walls of the outer shaft means, the shaft portions of the outer shaft means having axial projections on a side thereof extending through and with a circumferential size less than that of said annular recesses, the shaft portions of the outer shaft means having recesses therein on the opposite side from said annular recesses, the projection of one of the outer shaft means extending through said separating means and engaging in the recess of the subsequent shaft means, the shaft portions of the inner shaft means having means engageable thereon by an axial displacement thereof in order to connect them for jointly rotating.
In this patent the two pistons operating in each cylinder rotate with a cyclically variable speed: however, as clearly stated in claim 2 of this patent, the single pistons operating in different cylinders are coupled on the same axis with such an angular displacement that each piston has, with respect to the adjacent piston of the adjacent cylinder, an angle equal to the ratio of 360.degree. and the number of the cylinders of the engine.
Accordingly, this mechanical arrangement provides a maximum compression condition in the several engine cylinders for mutually fixed angular positions.
This construction has been selected by Mutzinger in order to obtain an equilibrium condition of the main rotating masses of the engine.
On the other hand, such a mechanical construction constrains the size of gas ducts and provide said ducts with two elbows each, since the engine cylinders are arranged along the same axis.
Thus, the main object of the present invention is to overcome the above mentioned drawbacks of known rotary internal combustion engines, by providing such a rotary engine in which all of the component parts are perfectly balanced, both from the static and from the dynamic standpoint, with a very simple mechanical construction.
Another object of the present invention is to provide such a rotary engine the pistons of which are so arranged and balanced as to locate the maximum compression angular position of the cylinders at a zone adapted to greatly reduce the gas duct length.
Another object of the present invention is to provide such a rotary engine including means for homologously coupling the engine pistons so as to provide an identical movement pattern for the coupled pistons and identical variations of the movement pattern as the engine compression ratio is changed.
Another object of the present invention is to provide such a rotary engine which has a high power jointly with a very even torque, both owing to the possibility of obtaining a greater number of complete operating cycles for each revolution of the driving shaft and a high rotation speed as a consequence of a complete elimination of the engine reciprocating masses.
Another object of the present invention is to provide such a rotary engine which does not comprise valve means, which would be not compatible with high revolution speeds, and in which the gas passage ports can be constructed with a comparatively large size.
Another object of the present invention is to provide such a rotary engine having a compression and scavenging ratio much larger than that of a conventional two-stroke engine with a complete independence of the angular duration of the respective phases of the operating cycle, which has been obtained, according to the invention, by using two identical mechanisms held in separated and adjoining cylinders, in which one of these mechanism operates to suck and compress the fresh mixture, while the other mechanism operates as a combustion-expansion mechanism, this mechanical arrangement affording a great reduction of the dead spaces of the gas ports, a complete elimination of the fresh mixture loss, since the scavenging is performed by not carburetted air, and an increase of the burnt gas expansion phase.
Another object of the present invention is to provide such a rotary engine which can operate with different types of fuels, by instantaneously adapting the compression ratio to the characteristics of the selected fuel, thereby practically providing an effective multiple-fuel engine.
Another object of the present invention is to provide such a rotary engine with a very reduced atmospheric pollution, owing to the possibility of fitting the compression ratio to the load of the engine, mainly for low revolution speeds.